Aqueous synthesis of thiol-capped CdTe nanocrystals:: State-of-the-art

被引:706
作者
Rogach, Andrey L.
Franzl, Thomas
Klar, Thomas A.
Feldmann, Jochen
Gaponik, Nikolai
Lesnyak, Vladimir
Shavel, Alexey
Eychmueller, Alexander
Rakovich, Yuri P.
Donegan, John F.
机构
[1] Univ Munich, Ctr Nano Sci, Dept Phys, Photon & Optoelect Grp, D-80799 Munich, Germany
[2] Tech Univ Dresden, D-01062 Dresden, Germany
[3] Univ Dublin Trinity Coll, Dept Phys, Semicond Photon Grp, Dublin, Ireland
[4] Univ Dublin Trinity Coll, CRANN Res Inst, Dublin, Ireland
关键词
D O I
10.1021/jp072463y
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
We report on the state-of-the art synthesis and improved luminescence properties of thiol-capped CdTe nanocrystals (NCs) synthesized in water. The optimized pH (12) and molar ratio of thiol to Cd ions (1.3:1) increases the room-temperature photoluminescence quantum efficiency of as-synthesized CdTe NCs capped by thioglycolic acid (TGA) to values of 40-60%. By employing mercaptopropionic acid (MPA) as a stabilizer, we have synthesized large (up to 6.0 nm in diameter) NCs so that the spectral range of the NCs' emission currently available within this synthetic route extends from 500 to 800 rim. Sizing curve for thiol-capped CdTe NCs is provided. In contrast to CdTe NCs capped by TGA, MPA-capped CdTe NCs show up to 1 order of magnitude longer (up to 145 ns) emission decay times, which become monoexponential for larger particles. This phenomenon is explained by considering the energetics of the Te-related traps in respect to the valence-band position of CdTe NCs. The correlation between luminescence quantum efficiencies, luminescence lifetimes, and Stokes shifts of CdTe NC fractions is demonstrated, being in agreement with a model proposed previously that connects the emission properties of NCs with their surface quality determined by the Oswald ripening conditions during growth. imaging, and plasmonics.
引用
收藏
页码:14628 / 14637
页数:10
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